Borehole flowmeter



4 Sheets-Sheet l Filed April 24, 1947 INVENToR. .lo/m M Pearson M@ Y Aornqys Sept. 8, 1953 J. M. PEARsoN 2,651,370 BoREHoLE FLowMETER Filed April 24, 1947 4 Sheets-Sheet 2 A INVENToR. John M. Pearson Sept. 8. 1953 J. M. PEARsoN 2,651,370

BoREHoLE FLowMETER Filed April 24. 1947 4 Sheets-Sheet 3 Patented Sept. 8, 1953 BOREHOLE FLOWMETER John M. Pearson, Swarthmore, Pa., assignor to Sun Oil Company, Ph

ration of New Jersey ladelphia, Pa., a corpo- Application April 24, 1947, Serial No. 743,646

Claims.

This invention relates in general to well bore ilowmeters and particularly to that class of flowmeters adapted to transmit acoustically a measure of the iiow of subterranean fluids employed to increase pressure in lower lying oil bearing strata.

In obtaining crude petroleum in the eld, it is a common experience to have the pressure within the producing horizon decrease so that it is necessary to increase the oil flow to adjacent wells by introducing water under pressure to the oil bearing strata through former oil wells selected near the periphery of and within the producing eld. Water is often piped from various sources and forced into these flooding wells. In some elds water bearing sands which overlie the oil strata are the sources from which water is permitted to ow downward into the oil reservoir and create the necessary pressure by building up a hydrostatic head proportionate to the depth of the water in the input well.

Water or other iiuids used to create pressure in the oil bearing strata should be carefully measured and controlled to avoid over-flooding the oil sands and, consequently, losing the oil residue. It is, therefore, a principal object of this invention to disclose a form of apparatus for measuring the flow of fluid admitted, through iiooding wells, to oil bearing strata as an aid to producing crude petroleum in the field.

Another object is to provide apparatus for measuring water admitted to oil bearing strata as a pressuring medium where the water bearing sands are above the oil sands as is common in certain oil fields.

Still another object is to eliminate all cables or electrical conductors as a necessary part of the equipment to be lowered into a well borehole and to confine the necessary apparatus to a rotating vaned flowmeter mechanically actuated by the ilow of iiuids descending in the borehole to operate a striker for producing acoustical vibrations. Cable conductors to carry signals from the striker in the well hole to the recording instrument on the surface are eliminated by suspending the striking mechanism from a vibration transmitting member such as a sucker rod and passing the vibrations along such member to the ground surface.

These and other objects will be apparent during the course of the following description and drawings, in which:

Figure 1 is a diagrammatic view of the apparatus.

2 Figure 2 is a sectional elevation View of the flowmeter.

Figure 3 is a sectional elevation view of Figure 4 on line 3 3.

Figure 4 is a sectional view on line 4-4 of Figure 2.

Figure 5 Figure 2.

Figure 6 is an elevational view in section of the stator and rotor elements.

Figure 7 is a sectional View on line 1 7 of Figure 2.

Figure 8 is a longitudinal cross section of a Ilow control.

Figure 9 is a circuit system.

Figure l0 is the section shown in Figure 6 showing removable orice plugs.

The complete borehole owmeter is diagrammatically shown in Figure 1 where the preferred embodiment of the device is illustrated. A flow guiding device I0 such as a hookwall packer is threadably attached to the adjustable flow control Il whichy in turn is connected to the flowmeter and flow indicating device striker unit l2. The downward flow of water from the strata I3, admitted through perforations in the casing generally indicated at I4, operates the liquid volume indicating striker as fully described later. A vibration transmitting member I5 suspends the ilowmeter and volume indicating striker unit l2 in position within the well bore casing I6 and is periodically vibrated by the volume indicating striker. An electrical amplifier circuit Il, shown diagrammatically in Figure l, receives the vibrations set up in the vibration transmitting meinber l5, through a mechano-electro transducer l5, and transmits the vibrations as pulses to a counter I9. A battery 20 is indicated as the source of power to operate the electrical circuit. The acoustical receiving, amplifying and counting device is shown mounted at the top of the well borehole for clarity. That all parts of che electrical system but the transducer will operate at a point distant from the well, will be readily understood.

Referring to Figure 2, the iiowmeter of the rotatable impeller type, adapted to actuate a volume indicator striker to periodically vibrate the vibration transmitting member, is shown. Although the ilowmeter is described fully herein, the details of this element represented by this gure are not claimed in this application but are is a sectional view on line 5-5 of diagram of the electrical reserved and form a separate case issued as Patent No. 2,571,058, October 9, 1951. The housing H is internally divided into an upper and a lower chamber. The upper chamber is filled with lubricating oil and, in this disclosure, includes the liquid volume responsive mechanism. The lower chamber contains the stator ring and the vaned rotor and is open to the free downward passage of the well uids. At the upper end, housing H is welded to the vibration transmitting member I5 so that the anvil 49, which is an extension of this member, projects into the body of the housing in proximity to the volume indicating striker or hammer 41. Housing H is threaded at the lower end to receive a flow control or a flow guiding means such as a well bore packer where conditions of flow do not require the control of the fluid flow through the flowmeter (Figure 1). Aperture 2| permits the fluid to flow out of the housing after it has caused vaned rotor 22 in the lower chamber to rotate. An orifice plate 23 is welded at any convenient location within the housing H below the vaned rotor. The orifice 23 is of preedtermined size and shape to cause theflowmeter to function at the peak eiciency by keeping the statorand rotor flooded. The efficient operation of the flowmeter under varying heads of fluidpressure, is further controlled by an adjustable flow control (Figure 1) which may be used as conditions require and which is described later.

A plurality of apertures 24 admit the fiuid into the lower chamber of housing H so that it passes downward through angled nozzle openings 25 in the stator ring 26 and is deflected against rotor 22 at the proper angle. As part of the stator ring 26, the stator plate 26a spans the diameter of the housing at this point. An insert 26h in which a bushing V26o is supported, permitting the shaft 21 to pass freely therethrough, is removably inserted in the center of stator plate 26a. Bushing 26e is made of the same material as shaft 21 to prevent electrolytic action. f

Figure 6 illustrates the position of nozzle opening 25 relative to vaned rotor 22 -which directs the fluid prior to impingement on the vaned rotor. Also shown in this gure is a removable plug P, held in nozzle opening 25 Yby set screw T. Such a plug may be inserted in any combination of nozzle openings to change the range of flow rates measured by the .fiowmeterby giving the limited quantity of fluid more momentum in its action on the rotor. Under greatly reduced hydrostatic heads of well fiuid interchangeable nozzles R of reduced cross-section may be inserted in the nozzle openings 25 and held in position by set screws T shown for holding plugs P, as illustrated in Figure 10. In summary, it will be evident that the capacity ofthe flowmeter and liquid volume responsive unit is made very flexible by several adjustments possible, for example, changing the orifice plate, inserting the proper size nozzle opening, by plugging one or several nozzle openings, or by any combination of these adjustments. When the range of the meter has been chosen, the actual flow rate can be mechanically adjusted by the flow control under those conditions where it is used. Returning to Figure 2, the circular motion of vaned rotor 22 is transmitted through shaft 21 centrally disposed within housing H, and supported by bearings 28 and 29, to the volume responsive mechanism here shown in the upper chamber of the housing.

Before tracing the rotary motion through the gear train to the final operation of the volume indicator striker or hammer 41 in the upper chamber, several features of importance in the lower chamber of housing H should be explained. Immediately above the stator ring 26 and resting on stator plate 26a, a spider ring 3|), shown in plan view in Figure 7, is centered around the lower projection of oil cup 3 I. This spider, composed of a supporting ring 5| (see Figure '1) and equally spaced vertical vanes 52, is designed to fit snugly around the lower projection of oil cup 3| and breaks any turbulent action as a result of rotation induced between shaft 21 and stator plate 26. A labyrinth 32, in close but not frictional contact with shaft 21, is let into the lower projection of oil cup 3| immediately below the clearance of the base of the cup and the shaft 21 through which the lubricating oil freely passes, to resist the upward flow of the well fluids. The space between oil cup 3l and the outside sleeve 33 is generally filled with the Well fluid being measured up to a level approximating the top of spider 30 as shown in position `in Figure 2. Above the level of the well uid, the remaining volumes between the oil cup 3| on the inside and sleeve 33 on the outside is filled with a light machine oil. A screen 34, cylindrical in shape, is mounted between the upper part of oil cup 3| and the bracket or shield 35v which suspends bearing 28. The shield 35 is of solid construction to prevent contact between the lubricating oil within the shield and that surrounding it in the space defined by the oil cup 3| and is suspended from bearing plate 33a which, in turn, rests on sleeve 33. A plate 35a closes the bottom of the shield 35 and positions the oil cup 3| by bolts passing upward into the shield, as shown, in fixed space relation. This plate 35a clears the shaft 21, as shown, and is apertured as at N to transmit pressure through the lubricant in and around the oil cup 3|. The screen 34, normally of a mesh of wires per linear inch, is inserted to transmit the pressure caused by the well fluid backing up around spider 30. Later, in the discussion of the operation of the flowmeter, a detailed explanation of the purpose of the screen 34 will be given.

Reference is now made to Figures 3, 4 and 5 in conjunction with Figure 2 for an understanding of the rotary motion transmitted through the reduction gear train of the liquid volume responsive mechanism in the upper chamber of housing H. The rotary motion of shaft 21, actuated by the rotor 22 of the ilowmeter, is transferred to gear wheel 36. The rotation of splined shaft 31, which forms the shaft of gear wheel '35, is transferred to gear wheel 318. The splined shaft 39 of gear wheel 38 transmits rotary movement to gear wheel 40 with which it meshes. Shaft 4|, to which gear wheel 40 is keyed, passes through bearing plate l2 and rotates cam 43 which is.

also keyed to it. Lug 44, fastened in a slot in rod 45 cooperates with cam 43 which retracts it once during each rotation through 360. Cam 43 is shaped to engage lug 44 at its uppermost position on a smoothly downward curving surface which, in rotating, moves the lug and attached rod 45 downwardly and aw'ay from engagement with the anvil 19. Spring 46 is compressed as the cam depresses the lug 44 moving rod 4'5 and hammer 41, which is attached to the plunger, downward in guide 48. When the full rotation of 360 is completed, cam 43 releases lug 4.4 suddenly, releasing the compression in aecnsvo:

spring 46 and allowing hammer 41 to hit the anvi1'49 on the bottom of the vibration transmitting member l5, setting up acoustical vibrations therein. It will be understoodfrom the foregoing that the vaned rotor of the'flowmeter will rotate many times to each blow of the volurne indicating striker on the vibration transmitting member anvil. The flowmeter is designed to respond to the passage of a known quantity of liquid through it. This quantity is required to be above a non-operating minimum initially established by the number and size ofthe nozzles in the stator ring and the size of the fixed ori'- ce. Any quantity of liquid below this minimum is insuiiicient to ilood the rotor and will not correctly operate the device. When the operating volume is passed through the flowmeter, Vthe re' sponsive striker indicates the passage and the ilow into the well can be accurately determined. The minimum flow rate for continuous operation is known and used as part of the calibration.

Although the functions of the separate parts of the iiowmeter and volume indicating device will be clear from the above detailed descriptions, the operation will be discussed in broad terms for purposes of clarifying the overall operation with emphasis on the features which permit -sustained `operation While submerged in the liquids being measured. Plug 50 permits forcing lubricating oil into the upper chamber of housing H preparatory tc lowering the device into the well casing. To preserve the lubrication of all gears and bearing-s and prevent the well uids from washing away the lubricating oil, care must be taken to prevent air bubbles and leaks from interfering with the complete filling vof the upper chamber in the housing body. This is accomplished by connecting a source of lubricating oil under pressure to the lopening for plug 50, inverting the nov/meter and removing the insert 2Gb. The' lubricant is then forced into the owmeter in this inverted position until it flows out the `opening usually closed by the insert. This insures the elimination of allA air pockets in theY device. To prevent bubblesv of air forming in the lubricant, the meter is kept inverted until used. A lubricating oil of the type(l used to lubrica-te light machinery has been found to be the most satisfactory.

Under pressure the lubricating oil will fill all the upper chamber of the flowmeter housing above the stator ring 26 and within the sleeve 33. The remainder of the housing from the apertures 24 downward and outside sleeve 33, designated as the lower chamber, will be lled with the well liquids under operating conditions. As the pressure of the liquids increase due to the depth of liquid in the borehole in which the flowmeter is operating, the well liquids will back-up around shaft 21 and surround the spider 30. The labyrinth 32 will present greater resistance to the liquid iiow by reason both of capillary forces and by close clearance than is in the open space .between the sleeve 33 and the oil cup 3l, causing the inflowing liquids to displace oil from internal and external hydraulic pressures are equalized, without displacing the oil in labyrinth 32. The lubricating oil, normally filling thisl ing oil in the oil cup 3l with the pressure outside the cup, thereby maintaining lubrication 'of "the lower vbearing V28 and maintaining the labyrinth ,65 the volume, including the baille 30, until thev I' mits the pulse along 32'fullof oil.V The shield 35, being of solid construction, prevents any turbulence caused by the rotation of .shaft 21 from being transmitted to the lubricating oil in the oil cup, thereby assisting the undisturbed exchange of pressure. The undisturbed transmission of pressure maintained without turbulence by the construction and location of the shield 35 and the spider 30 maintains proper and constant lubrication of the bearings and prevents the well liquid from rising in the'owmeter. With the hydraulic pressures equalized, capillary forces maintain the labyrinth 32 full of oil under all operating conditions. As the screen 34 is a ne mesh and is wet with oil, water droplets, which may become mixed with the oil, are refused passage. The shaft 21 supported in the lowermost bearing 28 passes through `plate 35a, the lower wall of the oil Cup 3|, stator plate 26a, the labyrinth 32 without frictional contact. This clearance permits the free circulation of lubricating oil and well liquids in pressure exchange contact. The apertures N in plate 35a are located so as to miss the solid shield 35, yet transmit the pressures in the lubricating oil within the oil cup 3l downwardly to the labyrinth 32 and upwardly to bearing 2,8 through the clearances around shaft 21., thereby resisting the upward flow of the well liquids along that path and diverting them around the oil cup 3| in the space and adjacent `sleeve 33.

For purposes of the most accurate readings, field tests show that the capacity of the meter used for illustration is between barrels per day and 1000 barrels per day. For the lower 4flow rates plugs P (Figure 6) are inserted in several of the angular nozzles 2.5 of stator ring 52B and retained in place by Ia set screw T or other arrangement. In the device shown, four 'nozzlesr are drilled into the stator may be increased, if desired, or decreased by plugging as described. In addition, interchangeable nozzles R of different cross sectional areas as indicated in Figure l0, held in place by set screw T, may be inserted in the original opening thereby increasing the force of the jet of well fluid against the rotor. Either method lowers the minimum iiow rate which can be measured.

This description of the two-chambered iiowmeter with emphasis placed on the lubricating and adjustable features, discloses the mechanism which adapts it to the measurement of fluid, and acoustic transmission of the readings. The rotary motion of the vaned rotor 22, actuated by the downward passage of the well uids through nozzles 25, is transmitted to the reduction gear train of the liquid volume responsive mechanism in the upper chamber of housing H, clearly shown in Figure 2. The rotation of gears 35, 38 and 43 cooperating with the splined shafts to which each gear is xed as clearly illustrated in Figure 4, actuates cam 43 at a fixed ratio (above the minimum flow required to operate the mechanism) to the .quantity of well fluid passing through vaned rotor 22. The liquid volume indicating striker mechanism is then activated. Hammer 41 is retracted by cam 43 moving lug 44 vdownward. Spring 4S is gradually compressed until the cam 43 has revolved through 360 when the ring.. This number .sudden release permits the spring to drive hammer 41 sharply against the anvil 4S. The vibration transmitting suspending member l5, of which anvil 49 is a part, receives the vibration set up byhammer 41 striking anvil 49 and transthis suspending member to the top of the well as shown in the diagrammatic sketch Figure 1.

One form of adjustable flow control I I (Figure 1) adapted for use under varying pressure conditions is shown in longitudinal cross section in Figure 8. Field tests indicate that oil horizon intake rates vary with time, so that it is sometimes desirable to throttle the fluid as it leaves the outlet opening of the flowmeter. A proper adjustment of the outlet insures correct flooding rate of the rotor according to measurement of the quantities of fluid passing through the flowmeter. In the preferred arrangement, a flow control of this nature must be capable of adjustment from the ground surface and of design which will not be injured by the downward passage of sand and gravel. It is also possible to use additional xed orifices similar to the orifice plate included in the flowmeter housing but it is then necessary to remove the iiowmeter each time an adjustment is made. Referring to Figure 8, which illustrates one form that may be used, the adjustable flow control II (Figure l) is enclosed in an outer tube which is threadably connected in three sections 60, 8l and 62. Threaded connector 63 is adapted to engage the male threaded section on the bottom of the housing of the flowmeter and pass the downflowing well fluids to the flow control. Connector 63 engages an inner tube 64 at threaded portion 65 and is free to transmit vertical movements of the vibration transmitting suspending member made at the top of the well. To enable the flow guiding device I0, such as a hookwall packer (Figure 1), to be rotated into place in the well casing, inner tube 64 is splined externally at 66 and cooperates with like internal splining in housing section 66. Inner tube 64 is upset into a hammer 61 which will strike anvil surfaces 68 and 66 of the outer tube section 6I upon the proper movement of the suspending member at the ground surface, to firmly set or loosen the packer in the well casing. Coil spring 18 is shown inserted between the lower face of hammer 61 and anvil 69 to meet conditions where the ow guiding device requires a constant load to fitV tightly in the well casing. Inner tube 64 is shown as extending downward through the lower section 62 of the flow control outer tube and terminating in a sleeve valve seat 1 I. A sleeve 12 with two V port openings 13, only one of which is shown, is mounted within the lower section B2 of the flow control outer tube acting both as a guide and a port opening. The flow guiding device or packer is threadably connected to the lower section 62 of the outer tube at lll. In operation, the adjustable flow control member is mounted between the flow guiding device on the lower end and the flowrneter above. The inner tube 64 will be positioned within the outer tube by the.v upward or downward movement of the lowmeter as adjusted by the vibration transmitting suspending member, while the outer tube will be held in place by the tightly wedged flow guiding device or packer which has been firmly seated in the well casing. The operation of the acoustical liquid volume responsive striker unit as disclosed above will indicate the necessity of opening or closing ports 13 to obtain the desired flow rate. If it is necessary to .permit a greater flow of well fluids through the fiowmeter, the ports; can be opened by moving the suspending member upward and thereby uncovering a greater area of V ports 13. Conversely, lowering the suspending member closes the V port and reduces the flow rate through the meter. The eilluent from the fiowmeter passes downward, as indicated by the arrows, through connector 63 to the bottom of sleeve 64 and out through opening 15 to ports 13 and then to the flow guiding device or packer through threaded opening 14. The illustration shows the flow control in closed position. The iiow arrows indicate the path of the borehole liquids when it is opened suicient to uncover a part of the ports 13. A vigorous upward movement of the suspending member causes hammer 61 to strike anvil 68 to provide the jar sometimes necessary to loosen the flow guiding device for its removal. Except for the purpose of seating or unseating the flow guiding device, the hammer 61 and anvils 68 and 69 have no function in operation of the flowmeter and ow control.

Figure 9 illustrates a typical form of the electrical system used to cause the vibrations, set up as pulses in the vibration transmitting member, to actuate an electro-magnetically driven counter. The transducer I8 previously referred to which may be of any one of numerous types, for example a conventional crystal phonograph pick-up, the needle of which engages the upper end of the member I5, delivers its output to an amplifier comprising the pentodes and 8| conventionally connected but desirably arranged with variable condensers at 86, 81, 88 and 89 to provide proper filtering by suppression of low and high frequencies to secure the optimum signal to noise ratio. A potentiometer at 82 acts as an adjustable attenuator to control the signal strength.

The amplified pulses are delivered to a cold cathode gas triode 83, the anode of which is supplied from a source of high positive potential through a high resistance 91 serving to charge the large condenser 90. These elements are chosen so that sustained pulsing of the tube does not occur and so that when the tube is fired the arc is extinguished, the current flow through the resistance 9| being insufficient to sustain the arc. The cathode circuit of the tube includes the protective resistance 92 and the relay 84 which serves to control a conventional electro-magnetic counter indicated at 85. When a signal is transmitted to the tube of the grid 83 it will fire,

the condenser discharging and giving rise to a pulse suicient to close momentarily the contacts of relay 84 as shown in Figure 9, and thus pro- Ivide an advance of the counter. The time constant of the circuit 90, SI is such that even though the signal to the gas tube grid is oscillatory only one cathode pulse occurs during the complete period of the signal. The result is that the counter will be advanced only one step for each signal. Due to the filtering action in the amplifier there will reach the gas tube to fire it only the desired signals, the tube not being affected by background noises.

The above description of apparatus for the measurement of well pressuring liquids admitted to oil bearing strata discloses a preferred embodiment of the invention. Means are provided for the continuous measurement of the pressuring liquid over long periods of time without interruption by the use of a flexible adjustment for efficient operation when required to meet varying conditions. The accuracy of the readings obtained enable the recovery of the maximum of the residual petroleum without danger 0f loss by over-flooding the oil bearing strata.

While the preferred form of the invention has 75 been disclosed, various changes may be made in the construction and application of the apparatus by those skilled in the art without departing from the spirit of the invention as claimed.

I claim:

1. Apparatus for measuring the flow of liquids in boreholes comprising a vibration transmitting member extending into a well borehole; liquid volume responsive means in operating engagement with the lower end of said vibration transmitting member; a flo'wmeter having an inlet and an outlet adjacent the volume responsive means adapted to periodically actuate said means to vibrate the transmitting member as predetermined quantities of liquid pass therethrough; concentrically arranged tubular means connected to the outlet of the owmeter having apertures therein between the tubes and having a part thereof slidable relative to a substantially xed section to regulate the flow of liquid through said iiowmeter by varying the exposed areas of the apertures to control the volume of eilluent therethrough; packing means, apertured longitudinally thereof, connected to the bottom f said tubular means to hold the relatively xed section of the same immovable relative to the borehole; and means operatively engaging the upper end of said vibration transmitting member to receive and register the vibrations.

2. In an apparatus for measuring the flow of liquids in boreholes, comprising a vibration transmitting member adapted to extend into a well borehole, a liquid volume responsive means in operative engagement with the lower end of the vibration transmitting member, a flowmeter,

having an inlet and an outlet, adjacent the volume responsive means adapted to periodically engage said means to vibrate the transmitting member as predetermined quantities of liquid pass therethrough, a liquid-permeable packer at the lower end of the apparatus, and liquid ow control means between the flowmeter and the packer: the improvement in which the liquid flow control means comprises an outer tube adapted to be maintained in xed relation to the borehole, an inner tube adapted to receive eilluent from the owmeter outlet and between and concentric with both said tubes a tubular sleeve, said outer tube sealed at its upper end from the flowmeter and open at its lower end to said packing, the sleeve at its upper end being secured to and sealed from the outer tube and at its lower end closed from communication with the outer tube and the packing, the sleeve having a longitudinally extending opening to allow iiow of liquid therethrough to the outer tube, the lower end of the inner tube being ported to allow llow of liquid therefrom into and through said opening and being longitudinally slidable relative to the sleeve and outer tube to thereby uncover variable areas of said opening and thereby control the volume of eiiluent liquid flowable from the inner tube to the outer tube.

3. Apparatus for measuring the flow of liquids in boreholes comprising a vibration transmitting member extending into a well borehole; liquid volume responsive means in operating engagement with the lower end of said vibration transmitting member; a lowmeter having an inlet and an outlet adjacent the volume responsive means adapted to periodically actuate said means to vibrate the transmitting member as predetermined quantities of liquid pass therethrough; liquid ilow control means adapted to receive the eiiiuent from said ilowmeter, said means including an inner tube connected to the iiowmeter outlet, an outer tube in sliding contact with the inner tube at the top and open at the bottom for unobstructed now of liquid therefrom, a sleeve having slotted openings in the walls thereof secured within the outer tube and closed at the lower end to enclose the lower end of the inner tube, said inner tube having an outer wall portion in sealing engagement with the inner wall of the slotted sleeve; and a packing member in engagement with the bottom opening of said outer tube being apertured longitudinally to in to adjust the flowmeter eiiiuent control by vertical movement of the vibrating transmitting member.

4. A device adapted for use as an element of an apparatus for measuring the flow of liquids in boreholes and being adapted to regulate the flow of liquid through the apparatus; said deouter tube open at its lower liquid, an inner tube centrally disposed in the outer tube and open at its upper end to admit liquid, and a sleeve concentric with and located between said tubes, said sleeve being at its upper end secured to and sealed from said outer tube and closed at its lower end, said sleeve having a longitudinally the inner tube being ported to allow flow of liquid therefrom into and through said opening and being longitudinally slidable to uncover variable areas of the opening to thereby control the ow of liquid from the inner tube to the outer tube.

5. A device to regulate the flow of fluids therethrough comprising an outer tube, having an opening in the outlet end for the low of liquid therefrom, and adapted to be held in a substantially fixed position; a slidable inner tube centrally disposed in said iixed outer tube and open liquid therethrough; and a sleeve openings in the walls thereof secured within the fixed outer tube and closed at its lower end to surround the lower end of said slidable inner tube, said inner tube having an outer wall portion in sealing engagement with the inner wall of the slotted sleeve and slidable therein to uncover portions of the area of the slotted openings for the controlled iiow of liquid t-hrough the device.

JOHN M. PEARSON.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 582,874 Price May 18, 1897 1,440,778 Foster Jan. 2, 1923 1,652,472 Erwin et al. Dec'. 13, 1927 1,871,319 Griswold et al Aug. 9, 1932 1,974,868 Hewgley Sept. 25, 1934 2,153,254 Johnston et al Apr. 4, 1939 `2,379,138 Fitting et al June 26, 1945 

